Drills for clearing obstructions in arteries

ABSTRACT

A DRILL FOR CLEARING SMALL DIAMETER TUBES SUCH AS ARTERIES COMPRISES A ROTATABLE BIT SURROUNDED BY A NON-ROTATING SHIELD INTEGRAL WITH AN OUTER FLEXIBLE TUBE THE OTHER END OF WHICH IS GRIPPED IN A DRILL BODY. AN INNER FLEXIBLE TUBE LIES WITHIN THE OUTER TUBE ANE EXTENDS TO A POINT JUST SHORT OF THE BIT, ITS OTHER END ALSO BEING GRIPPED IN THE DRILL BODY. A FLEXIBLE SHAFT EXTENDS FROM THE BIT TO WHICH IT IS FIXED, THROUGH THE INNER TUBE AND A BEARING IN THE DRILL BODY FROM WHICH IT PROTRUDES TO A COUPLING MEMBER FIXED TO THE SHAFT. DUCTS IN THE DRILL BODY LEAD TO THE SPACE BETWEEN THE TUBES AND TO THE INTERIOR OF THE INNER TUBE ENABLING FLUSING LIQUID TO BE INTRODUCED TO AND WITHDRAWN FROM THE REGION OF THE BIT.

E. Moss 3,614,953 DRILLS FOR CLEARING OBSTRUCTIONS IN ARTERIES 0a. 2e,.1 s11 Filed Jan. 21, 1969 United States Patent US. Cl. 128-305 6 ClaimsABSTRACT OF THE DISCLOSURE A drill for clearing small diameter tubessuch as arteries comprises a rotatable bit surrounded by a non-rotatingshield integral with an outer flexible tube the other end of which isgripped in a drill body. An inner flexible tube lies within the outertube and extends to a point just short of the bit, its other end alsobeing gripped in the drill body. A flexible shaft extends from the bitto which it is fixed, through the inner tube and a bearing in the drillbody from which it protrudes to a coupling member fixed to the shaft.Ducts in the drill body lead to the space between the tubes and to theinterior of the inner tube enabling flushing liquid to be introduced toand withdrawn from the region of the bit.

This invention relates to drills for clearing obstructions fromsmall-diameter tubes, and has one application in clearing deposits inarteries.

Thrombosis is a well known medical condition which can lead to adangerous restriction of the blood supply to a limb. Eventually gangrenemay set in, leading to amputation of the limb. The condition may occur,for example, in the femoral artery of the thigh.

The present invention provides a drill which can be inserted in anartery to remove or reduce such occlusions.

According to the present invention a drill suitable for clearingsmall-diameter tubes such as arteries comprises small-diameter flexibleinner and outer tubes, a bit located at one end of the tubes and havingan exposed transverse cutting face, flexible drive means for rotatingthe bit, a non-rotating shield surrounding the bit but with spacebetween the bit and the shield and inlet and outlet ports for passingliquid towards the bit and withdrawing liquid from the region of the bitalong the inner tube and the space between the tubes.

Said shield may be an extension of said outer tube, and said flexibledrive means may be a flexible shaft extending within said inner tube.

To enable the nature of the present invention to be more readilyunderstood, attention is directed, by way of example, to theaccompanying drawings wherein FIGS. 1A and 1B taken together constitutea longitudinal section of an embodiment of the present invention.

FIG. 2 is an end-view of the drill shown in FIG. 1A.

In FIG. 1A and FIG. 2 are shown an outer flexible tube 1 and an innerflexible tube 2. Typically the tube 1 has an external diameter of 3 mm.Both tubes are made of polytetrafluoroethylene and may be of anysuitable length, e.g. 1 metre. At one end of the tubes is located a bit3 having flat side portions 4 and 5 with chamfered portions 6 betweenthem, and a transverse cutting face 7. The bit 3 is fastened to aflexible drive-shaft 8 of conventional coiled-wire construction. Thethickness of the bit between flats 5 is less than the internal diameterof tube 2, as shown in FIG. 2, so that the end of tube 2 is notcompletely sealed by the bit. The bit 3 is surrounded by a shield 9formed as an extension of the outer tube 1.

The other ends of tubes 1 and 2 are sealed to a frame 10 by clamping thetubes between male and female cone ice members 11, 12 and 13, 14respectively. Pipes 15 and 16, connected to the male cone members,constitute ports enabling liquid to be admitted to the inner tube 2, andwithdrawn from the outer tube 1 respectively; the liquid in the latterflows in the annulus between the two tubes. Shaft 8 passes through apolytetrafiuoroethylene bearing 17 to a coupling member 18 in which itis secured by a set-screw 19. Member 18 includes an offset hole 20 whichis engaged by a pin 21 of a disc 22 held in the chuck 23 of a highspeedelectric motor 24 of the type used in dentists drills, e.g. rotating at24,000 r.p.m.

In use the bit is inserted percutaneously or in an incision in theartery, and slowly passed down it. The exposed transverse cutting face 7of the bit removes occluding material within the artery, while theshield 9 prevents contact between the rotating bit and the artery wall,thus preventing damage thereto. Saline solution is fed via pipe 15 pastthe flats on the bit to the cutting face, and withdrawn via pipe 16carrying with it the fragmented deposits loosened by the rotating bit.Alternatively the solution may be fed via pipe 16 and withdrawn via pipe15.

I claim:

1. A drill for clearing small diameter tubes such as arteries comprisingsmall diameter flexible inner and outer tubes, a bit located near oneend of the inner tube and having an exposed transverse cutting face, aflexible shaft for rotating the bit, which shaft passes within the innertube and protrudes therefrom at both ends, a non-rotating shieldsurrounding the bit and forming an extension of the outer tube anddefining with said bit a space there between, inlet and outlet ports forpassing liquid towards the bit and withdrawing liquid from the region ofthe bit along the inner tube and the space between tubes, a body memberproviding an anchorage for the end of the outer tube remote from theshield, a port communicating with the interior of the outer tube, ananchorage for the end of the inner tube remote from the bit, a portcommunicaing with the interior of the inner tube, and beyond thelastmentioned end of the inner tube, a bearing for the flexible shaft,which is equipped with a coupling member at its end extending beyond thebearing at the side thereof remote from the end of the inner tube.

2. A drill for clearing small diameter tubes such as arteries comprisingtwo small diameter flexible concentric tubes which define a spacetherebetween, a bit located beyond one end of the inner concentric tubebut at least partially within said outer concentric tube with which itdefines a space, said bit having a cutting face which protrudes fromsaid outer concentric tube, a flexible drive means for rotating saidbit, and inlet and outlet ports for passing liquid towards the bit andwithdrawing liquid from the region of the bit along the space betweentubes and the space between flexible drive means and the innerconcentric tube.

3. A drill as claimed in claim 2 in which the bit has fiat facessubstantially parallel to one another and to the diametral plane of theconcentric tubes, wherein the space between said faces and the innersurface of said outer concentric tube allows material, cut by the bit,to pass.

'4. A drill as claimed in claim 2 in which the cutting face of the bithas two inclined cutting edges the inner ends of which meet at an obtuseangle on the rotational axis of the bit and protrude from said outerconcentric tube and the outer ends of said edges are surrounded by saidouter concentric tube.

5. A drill as claimed in claim 2 in which the port for passing liquidtowards the bit communicates with the space between the two tubes andthe port for withdrawing the liquid from the region of the bitcommunicates with the interior of the inner tube.

6. A drill as claimed in claim 2 in which the flexible drive means forthe bit is in the form of a flexible shaft passing Within the inner tubeand protruding therefrom at both ends.

References Cited UNITED STATES PATENTS 5 Schilow 1s 104.1

Slaughter 2724.1 Vogel 128276 Davis 27--24.1

4 Cooper 128276 X Sokolik 128311 Delaney 128303 X Muller 128-303 X U.S.C1. X.R.

